Mold for foamed latex



June 23, 1953 J. T. MARVIN MOLD FOR FOAMED LATEX 2 Sheets-Sheet 1 2 Filed April 18, 1950 m Arm/mm June 1953 J. 'r. MARVIN I 2,642,624

MOLDFOR FOAMED LATEX Filed April 18, 1950 2 Sheets-Sheet 2 Patented June 23, 1953 MOLD FOR FOAMED LATEX John T. Marvin, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware r Application April 18, 1950, Serial No. 156,677

I 1 Claim. 1 This invention relates to molds for foamed latices and the like.

It is, therefore, a basic object of the invention to provide a mold in which articles may be formed from foamed latex, which mold provides heat passages within the foamed latex and wherein the article molded has a relatively constant area throughout any planar cross section thereof.

In carrying out the above object, it is a furcurved. Cushions made in this manner are quite ther object to provide a mold for molding foamed satisfactory in resilience and use when being latex which includes a body portion and cover compressed in a direction parallel to the axis of portion, each portions of which having inwardthe tubular depressions in the cushion. I-Iowly extending, conically shaped, hollow protuberever, in an automobile seat cushion, for example, ances nesting in uniformly spaced relation when considerable .side sway is apparent during use t mold is closed, wherein the top portion of the cushion which Another object of the invention is to provide has no cored out sections therein tends to have a mold for molding an article made of foamed 'less side sway than the bottom of the cushion rubberlike material which is of a substantially which includes the cored portions. In order to uniform area t h t any planar os cobviate this diificulty and also to provide more tion thereof and which has less side sway and uniform curing, faster heat distribution, less resilient displacement than articles made in conrubber p r u Volume, the p t i venventional'types of molds. tion is directed to a mold as shown in Fig. 3 at Further objects and advantages of the pres- 20. The mold consists of a main body portion ent invention will be apparent from the follow- 22 which is,'in effect, a box having cars 24 thereing description, reference being had to the ac- 0n Which-include upwardly extending dowel p companying drawings, wherein preferred em- 26. A cover 28 is provided which has apertures bodiments of the present invention are clearly therethrough which register with the dowel pins shown I 26 so that the cover may be positively posi- In t drawings: tioned with respect to the base portion 22.

Fig 1 is a plan View of ubbeflike artide In order to get proper heat distribution within showing the inwardly extending cored portions the foamed latex, a plur y of evenly Spaced in solid lines, with dotted lines indicating the upwardly exte h0110W tu u r p o uberances placement of cored portions extending from the 30 are providedin the y Portion of the mold other Side thereof, The cover portion 28 is likewise provided with Fig. 2 is a cross section through the rubberlike 00111051115 Shaped h0110W protuberances 32 which artide taken on line z 2 of 1, are properly spaced as shown in connection with Fig 3 is Cross section of a m showing the rubberlike article shown in Fig. 1, so asv to relationship between t cores carried by th interspace between the protuberances 30 in the cover and those carried in the base section of base p These protuberances y be t 1 called cores since they actually core out the 4 is a plan View of t t of a m foamed latex and permit heat to be distributed Fig. 5 is a section taken on line 5-5 of Fig. 4, et rou h. The co es 3 andmay e of showing the construction used in fabricating y equal number and preferably are SO paced the mold. that their base sections will touch when pro-.

In the manufacture of foamed rubberlike ar- I jetted into a sin p an n' this mann ticles, such as foamed rubber seat cushions, asatisfactory uniform Spacing. is maintained bemattresses, and the like, it is necessary in the tween the conical Walls ofthe cores in' the cover curing of the foam to maintain a relatively thin and base sections as noted in Fig. 3. The article cross section in all portions of the foamed latex 4 i lf. as shown in Figs- 1 and 2 has a reverse within the mold. This is necessary to assure nfiguration of the mold. uniform heating during the curving of the latex In the manufacture of articles in molds, such compound. as disclosed herein, any number of cores may In practice, tubular protuberances or cores are be used, such conically shaped cores preferably have an apex angle of approximately 30. It is used on the base of themold which extend there- 2 from and in the foamed latex, which tubular protuberances carry steam or other heating medium into close contact with the mass of foamed latex being cured. In thismanner, there is no portion of the foamed latex within the mold which has a thickness greater than can be easily cured within a relatively short period of time, for example, l0 to 30 minutes as the case may be in accordance with the specific compound being apparent that this angle may vary widely in accordance with the thickness of the cushion being formed. Similarly, according to the specific overall area of the cushion, the number of rows of cores in both the base section and the cover section will vary considerably, the mold shown in the drawings merely being illustrative of one type' ofthe'mold. I

The mold 29 -may be made in'a number of ways. One of these is shown in Figs. 4 and 5 wherein the top 28 only of the mold is shown. It is un-' derstood that the base 22 may be made ina similar manner, that is to say, the coresm'aybe Referring spe attached in a similar manner-1 U 4 cifically to Fig. 5, the construction o'f 'the top28: is clearly shown wherein the top 28 comprises a plate 40 having a plurality of aperturesdltherethrough and spaced at proper intervals to accommodate the cores 32. 42 should be slightly less' than the base diameter of the conical'cores 32:- fonexample';inthe-order of three or four thousandths-of aninchw Each of the holes" 42 preferably-'include an undercut portion Mat the-outside-Of tIIe pIate 40"=and=-each' of the cores 3 2 preferably include an outturnedlip 46 thereonwhich fits snugly within the-un dercut' 4 3'; Thus" when the cor'es"32* are pressed through the holes 42 the base o'ff the cores are slightly deformed when the fiangesifi bottom in the :undercut portionl l whereby'the' cores 32 are held-firmly in place: In=order toassure' pi'o'per placement 'of the'cores 32=and to prevent 8115 1210 cidental displacement thereof a locking' plate dll' is provided which I includes a plurality; of aper= tures' 5d: therethrough. The apertures 50 are in the: samewpositionsirelative to the'p'late-48 as the' holes 42 in the plate' -M: Thus plate= Mrmay; be

superimposed orr tlie plate dll a'ndholes' 50 will line upwitli' the h'oles-MZ' e The holes i SKI- are of a predeterinined smaller diameter than i the portion: of" "the cores 32 over which theyfit: The .di'am'eter 'of the holes should be preferably; in the: ord'er' of three -to -five th'ou sandths of: an inch 7 less than' the-diameter of; the cores 32 a-t thepoint where'theyfipass through the plate 48;- Thuswherr the plate' 48 'is ipressed downwardly: over the cores 32, .theedges of the plate around"? holes' 50=- bite into' the i cores 3'2 as" at" 52 and permanentlyr lock-thee cores 5 in place against any accidental- 'displacement:

It is apparent thatithecores' may be positioned within the'ba'se portion in themold in a mam her as descri'bedhereinbeirer It is also ape may be utilized} for'example, .the coresmayI- be welded into the parts" of the moldfior m yh screwed 111' ii threads-"are provid'e'dori for tlrlat matter, may be attached: inanysuitable 'man ner, the metho'd di'sclose'd herein beifig a siinpli fied assembly f rocess: wherein simple drilling and/or pun'ching operations are' all- -that is -re' any. of I the: butalastic polymers wliich may be The diameter of hols- 4 gelled and cured, is foamed in the usual manner by beating air therein and compounded suitably so as to be capable of being cured. Into this foam is usually placed a delayed coagulant which will gel the foam in a short period of time after it has been placed in the mold. The base section 22 of the mold is then filled with the latex foam whichis"scrapedofiTlevel across the top thereof wliereupon the cover-2B isali'gned by the dowel pins 26 and pressed into place. In order to accommodate the displaced latex foam, vent holes may be provided in the cover, or during tne'scrapin'g' process, the level of the latex may be scraped to a predetermined level below the top ofi'thebasese'ction to compensate for the dispiaeemen'vwhenthe cover is in place. In any event, after the'cover is in place, the mold should be full of foamed latex whereupon the latex withiri a predetermined period gels through the action of the delayed coagulant. The mold with the-qgelledlatex'foam therein is next placed in a curing oven or retort and is curedin a suitable lengthiof time whereupon the mold-maybe disparent that otherm'eans of assemblingt-the coresassembled and'the cushion removed. It is-apparent that a mold lubricant should be'used on them'oldsections and any ofthe conventional lubricants are'satisfactory for this purpose.

Since the art offoamin'g, gelling'and curing latices forms no part of this invention, it isto be understood-that the disclosure here'is, 'in'no way; limited to'specific latices or'compounds, etc:

Whilethe embodiments of the present inven-' tionas herein disclosed, constitute preferred forms, it is'to-be understood that other forms might be adopted.

What is claimed is as follows:

A" mold for foamed-latex comprising in combination; a base portion and a" cover portiontherefor, at least one ofsaidportionsincluding a plurality of cores'set therein-and extending from-the outside of said niold portion there-' through, each of'said' coresincluding a flange abutting the outside surface of "said mold-portion for'preventingrfurther inward movement thereof with" respect to' the said" mold" portion; 1 and an apertured plate positioned at the mold side'of said mold 'portion and firmly pressed against-the surface of saidmold-portion' and'fi'rmly and simultaneously gripping all said cores for making the cores in place with respect to' sai'd-mold portion and for 'providing the mold surface.-

JOHN T. MARVIN.

RefrencesCited in the file of this patent- 434,550 Great Britain Sept. 4,21935' 

